DIY ESS - AC Charger terminals modification for Water Heater

Before moving all the ESS components to the metal cabinet, I decided to make a last modification to the charger side relay and AC terminals; Instead of having 6 relays for 6 chargers, I removed the 6th one AC wires and left the relay terminal free for my water heater command line (220V, 2A max) that activates the coil of a 220V 20A line that feed the water heater at night during off-peak hours. A signal sent by the utility closes a relay in my utility meter at night and opens it in the morning, and this is how the water heater runs only on low rate electricity. Closing the 6th relay on the same command line, I will be able to switch ON or OFF the water heater as a "6th charger" in a way, meaning, when all the chargers from 1 to 5 will have been switched ON already

If you get my kit, have no water heater - or a gas one, like many in the USA - , use the 6th relay for a charger - like I used too all this time - continuing the AC charger line up to relay 6, the behaviour of the 6th relay has not been changed at all, it is still the 6th charger from teh Arduino point of view !

Then I add to move two chargers on the same AC terminal/ relay twice, like you can see on the photo since I have 7 chargers

I also changed the program so that when the 5th charger comes ON, and the arduino sees that it uses too much power compared to the net power, instead of switching it back OFF, it switches the 1st charger OFF instead, making it more precise (so always install several chargers on the same line towards the end: 4th, 5th)